The purpose of this project is to monitor the patients' microbial flora which may give rise to infection, to determine sources of hospital acquired flora when possible, and to study characteristics of unusual organisms of clinical significance. Such organisms may be subspeciated by phage typing, serotyping or biotyping to allow determination of spread. A review of cultures, particularly blood cultures, revealed that during the last year gram-positive cocci outnumbered gram-negative bacilli as a cause of bacteremias. Staphylococcus epidermidis and streptococci both increased significantly in number. Antibiotic resistant coryneform bacteria are still encountered in the patients and further studies have been carried out to evaluate their characteristics. Nasal surveys for filamentous fungi confirmed the presence of the organisms in the air as has been shown in air samples. Staphylococcus aureus surveys of personnel showed the carrier rate to be sharply decreased.